The present invention relates to improvements in methods of and apparatus for transferring rod-shaped commodities which serve to filter tobacco smoke and carry and/or contain pulverulent, granular or otherwise configurated and/or dimensioned ingredients, e.g., particles of charcoal embedded in rod-like fillers of acetate fibers, crepe or the like. More specifically, the invention relates to improvements in methods of and in apparatus for transporting tobacco smoke filtering rods or plugs, which carry confined and/or adherent solid particles, or compel loose particles to advance, along an elongated path from a sender of a file of successive rods to a receiving station.
It is customary to advance a file of successive rod-like filters, normally filters of multiple unit length, along an elongated path which is defined by an elongated pneumatic conveyor in the form of a conduit. If the filters contain and/or carry solid particles, such as granules of charcoal, a certain percentage of solid particles becomes separated from the filters; this results in highly undesirable contamination of the conduit and/or of the parts at the receiving station. Stray particles of charcoal or the like are particularly undesirable at the receiving station because the operation of parts at such station is likely to be adversely affected to a progressively increasing degree unless the apparatus is equipped with suitable means for intercepting stray particles and/or those particles which are likely to become separated from the filters. Attempts to intercept, collect and evacuate solid particles from the path for successive filter rods of a file of such commodities are disclosed, for example, in commonly owned British specification No. 1 410 473 published Oct. 15, 1975 and in U.S. Pat. No. 5,556,236 granted Sep. 17, 1996. The means for admitting granules of charcoal and/or other solid particles can include so-called AC machines (distributed by the assignee of the present application) which sprinkle solid particles onto a running tow of filter material (e.g., acetate fibers).
An object of the invention is to provide a novel and improved apparatus which can gather and evacuate stray solid particles and/or readily separable solid particles from the path for filter rods for tobacco smoke with a degree of efficiency and reliability exceeding that of heretofore known apparatus.
Another object of the invention is to provide a novel and improved apparatus whose operation is not affected by the rate of delivery of filter rods from a sender to a receiving station.
A further object of the invention is to provide an apparatus which can reliably intercept, gather and dispose of stray solid particles ahead of the station which receives successive filter rods of a file of such commodities and which accommodates devices likely to be adversely affected by stray particles of charcoal or the like.
An additional object of the invention is to provide an apparatus which can intercept and evacuate high percentages of or all solid particles from the path for filter rods of unit or multiple unit length without affecting the quality (such as the configuration) of filter rods.
Still another object of the invention is to provide a novel and improved method of evacuating solid particles (such as granules of charcoal or dust of charcoal and/or other solid additives which enhance the filtering action of the filter rods and/or the flavor of tobacco smoke) from the path for advancement of a series of successive filter rods from a sender (e.g., a filter rod making machine) to a receiving station, e.g., a station which gathers filter rods preparatory to admission into the magazine of a filter tipping machine.
The invention is embodied in an apparatus for transporting tobacco smoke filtering rods (e.g., filter rod sections of twice, four times or six times unit length), which carry solid particles (such as fragments of charcoal) along an elongated path extending from a sender to a receiving station. The improved apparatus comprises a pneumatic conveyor which defines at least a portion of the elongated path and includes a section provided with openings serving to establish communication between the aforementioned portion of the path and a collecting chamber, and means for propelling (by way of the openings) at least some of the solid particles which become separated from the filtering rods not later than in the aforementioned portion of the path.
The conveyor preferably includes an elongated conduit and the openings can constitute slots provided in the conduit in the aforementioned portion of the path; such slots can extend at least substantially radially of the conduit.
The propelling means can comprise a source of pressurized gaseous fluid (e.g., compressed air) and means for directing gaseous fluid furnished by the source into the conveyor in the regions of the openings.
The conduit of the pneumatic conveyor can include a series of successive annular components which define the aforementioned portion of the path; the openings are then disposed between the successive annular components of the conduit and preferably constitute circumferentially complete slots.
The means for propelling pressurized gaseous fluid from the aforementioned source into the conveyor in the regions of the openings can comprise a pipe or duct receiving pressurized fluid from the source and extending along the aforementioned portion of the path; such duct has outlets (e.g., in the form of orifices or ports) serving to direct jets of pressurized fluid toward at least some of the openings. The duct is preferably closely adjacent to and can serve as a support for the collecting chamber and/or for the aforementioned annular components of the conduit.
The aforementioned portion of the path is or can be at least substantially vertical, and the conveyor is preferably arranged to convey the rods downwardly at least in the at least substantially vertical portion of the path. The particle-collecting chamber of such apparatus is or can be designed and mouted in such a way that it includes an upper portion above and a lower portion below the openings, and an outlet (such as a tubular extension of the lower portion) for collected particles. The chamber can at least partially surround the conveyor in the region of the aforementioned portion of the path.
Another feature of the invention resides in the provision of a method of transporting rod-shaped tobacco smoke filters, which carry solid particles along an elongated path from a sender to a receiving station. The method comprises the steps of directing into a predetermined portion of the path a plurality of jets of a pressurized gaseous fluid to thus expel from such predetermined portion of the path solid particles which are separated and/or separable from the filters, collecting the expelled particles in a chamber which is outwardly adjacent the predetermined portion of the path, and evacuating collected particles from the chamber.
The predetermined portion of the path is or can be at least substantially vertical, and the method can further comprise the step of conveying the filters downwardly into and through the predetermined portion of the path.
The evacuating step can include discharging collected particles from the chamber by gravity flow.
Still further, the method can comprise the step of braking successive filters downstream of the predetermined portion of the path.
The particles can include or constitute fragments of charcoal.
The method can also include the step of establishing a plurality of openings (e.g., in the form of arcuate or annular slots) for the expulsion of solid particles from the predetermined portion of the path into the chamber.
The pressurized fluid is or can be compressed air.
Still further, the method can comprise the step of changing the orientation of filters between the predetermined portion of the path and the receiving station.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling and operating the same, together with numerous additional is important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.